Development Of Injection Control System For Rotary Valve Engine

With the popularity of cars,the application of engines has been closely related to every citizen’s life.At the same time,a large number of engines bring great pressure to the social environment and energy.Universities and research institutions are constantly innovating and improving the engine structure and ECU system,constantly optimizing the engine operation structure and fuel emission index.By changing the structure of the engine,our laboratory realizes the design of rotary valve engine,and needs a set of corresponding fuel injection control system.At present,the rotary valve engine has not been applied in the market,and naturally there is no corresponding control system.Therefore,the development of the software and hardware of the engine fuel injection system is particularly important;the electronic control product(ECU)on the market is not open,and the general colleges and universities will encounter great difficulties if they want to develop the power generation control fuel injection system;the research institutions have to develop one by themselves Electronic control injection system,through the experiment to get the best air-fuel ratio,calibrate the injection map,and store it in the control system,realize the function of adjusting the engine injection according to different working conditions;pave the way for the follow-up study of engine power,economy and emission performance,so as to better drive the development of the automotive industry.In this paper,a set of electronically controlled fuel injection system for rotary valve engine is developed.The system uses stm32f103c8t6 single chip microcomputer to determine the engine speed by collecting the injection pulse width signal of the original engine ECU,the load of the engine is determined by the collected throttle position signal,and the injection quantity of the engine is determined by the speed and load.The designed hardware circuit includes the injection signal acquisition circuit The signal acquisition circuit of the oxygen sensor,the signal acquisition circuit of the throttle position sensor,the driving circuit and the serial communication circuit between the upper and lower computers are designed by using Altium Designer software design and draw the relevant signal acquisition circuit,fuel injection drive circuit diagram and serial communication circuit diagram;through mdk5 software to program STM32 microcontroller,complete the relevant library function programming,complete the drive fuel injection;at the same time,the engine speed and related fuel injection parameters are displayed in the host computer through the serial circuit.In this experiment,the control variable method is used to optimize the injection map,and the corresponding injection pulse spectrum optimization experimental data is obtained;the closed-loop drive injection program is burned into the single-chip microcomputer to complete the closed-loop drive experiment,and the corresponding experimental results are obtained.The collected experimental data are processed,and the relationship curve between the engine power performance and emission index and excess air coefficient λ is obtained And the external characteristic curve of the engine before and after optimization,and the correlation analysis,get the engine running emissions.The conclusion of the experiment proves that the injection control experiment is feasible and the development of the control system is successful.